Feedbutler - Subscribe to your RSS feeds directly via email!
Kill the Newsletter! - Convert newsletters into RSS feeds
follow.it - follow.it gets publishers more followers & recurring traffic, and provides a better reading experience for followers
Listmonk - Send e-mail campaigns from a powerful dashboard. High performance and features packed into one app.
FeedBlitz - FeedBlitz is a mega pack solution for social media marketing and RSS feed and subscriber integration.
Reeder - Reeder is an RSS reader and client for multiple services.